gistfile1.txt

#include <iostream>
#include <cmath>
#include <cstring>
#include <map>
#include <memory>
#include <vector>
#include <set>
#include <ctime>
#include <chrono>


#include <bitset>
#include <thread>
#include <cstdarg>

#include <fstream>
#include <mutex>


class Bucket2 {
public:
    bool ok ;
    int id ;
    Bucket2(int);
    //void dump(std::ostream &stream);
    ~Bucket2() {
        printf("%d %p %p\n",this->id,this);
        ok = false;
    }
};
Bucket2::Bucket2(int _id) {
    ok = true;
    id = _id;
}

std::shared_ptr<Bucket2>  oneBucket;
std::mutex            mtx;

double x;
void reader() {
    while ( 1) {
        mtx.lock();
        auto b = oneBucket;
        mtx.unlock();
        if ((bool)b) {
            x = b->id;
        }
    }
}

void writer() {
    int i=0;
    while ( 1) {
        //Bucket2 *bkt = new Bucket2(++i);
        //auto tb = std::shared_ptr<Bucket2>(bkt);
        mtx.lock();
        oneBucket = std::make_shared<Bucket2>(++i);
        mtx.unlock();
    }
}

int main(int argc,char** argv) {
    std::thread _th1(reader);
    std::thread _th2(writer);
    _th1.join();
}